Cargo cranes



April 19, 1960 3 Sheets-Sheet 1 Filed May 10, 1956 ATTORNEY April 19,1960 R. P. FOX 2,933,197

CARGO CRANES Filed May 10, 1956 3 Sheets-Sheet 2 Z6 INVENTOR Faber) PFor ATTORNEY R. P. FOX

CARGO CRANES April 19, 1960 3 Sheets-Sheet 3 Filed May 10, 1956 INVENTORfiab er'f P Fax BY m @710 I? a ATTORNEY United States Patent CARGOCRANES Robert P. Fox, Duluth, Minn., assignor to Clyde Iron Works, Inc.,Duluth, Minn., a corporation of Minnie sota Application May 10,1956,Serial No. 584,085

6 Claims, (Cl. 212-58) This invention relates to an improvement in shipmounted level luffing cranes used in general cargo service. The purposeof this invention is to provide pendulum dampening for the load bothradially and tangentially as related to the rotating center of thecrane. Generally, pendulum action is caused by acceleration anddeceleration of the crane swing, boom lufing, and ships roll.

A feature of the present invention is to support the load in the. bightof two cables that radiate from the load to the boom. to form, ineffect, an inverted tripod. The widely separated three points, ofsuspension at the boom produce a pendulum dampening or stabilizingeffect on the suspended load to resist horizontal motion in anydirection.

A second feature of the present invention is made possible by theforward, double cable leg of the inverted tripod heretofore described.The forward cables, at close proximity, permit the use of a moreconventional boom that tapers from. a wide hinge to a narrow tip. Thismay be contrasted to other forms of load dampening. devices that requireheavy, wire ended booms for dampening in the. radial direction only, asrelated to the rotating center of the crane.

A third feature of the present invention relates to the manner in whichthe load supporting cables are uitimately arranged to provide levelhiding, and equalized to avoid slack lines or unevenly loaded lines.This feature virtually eliminates torsional effect in the boom, therebypermitting lightweight boom design and eliminating cable fouling.

An added feature of the present invention lies in the provision of aload suspension of an inverted tripod type in which. the load supportingcables pass through sheaves on the load block. This arrangement permitsthe equalization of the load upon the lines in a novel and effective.manner.

Theseand other objects and novel features of my invention will be moreclearly and fully set forth in the following specification and claims.

In thedrawings forming a part of the specification:

Figure l is a side. elevational View. of a cargo crane showing thegeneral arrangement of parts therein;

Figure 2 is a top plan view of the crane boom showing the arrangement ofsheaves thereupon;

Figure 3 is a diagrammatic view showing the location of the hoisting,luffing, and swinging devices in the crane cab;

Figure 4 is a front elevational view of the cab. showing the arrangementof sheaves thereon; and

Figure 5 is a diagrammatic view of the load hoist lines showing thearrangement thereof; I

Figure 6. is a diagrammatic view of the boom'topping cable reeving.

The crane A is of the type used on ships and is designed for movementupon tracks supported on the deck of the ship. As an example, Figure 1indicates the ship deck having vertical supports 11. and 12 thereuponwhich support tracks 13 and 14 on which the crane is mounted. Verticalspacers 15 and 16 are provided extending upwardly from the tracks 13 and14 and support upper tracks 17 and 19, respectively. In other words, thetracks are channel-shaped in form including upper and lower railsbetween which the supporting wheels of the crane may run.

The crane A includes a base frame 26 having dOWI1- wardly extendingwheel supports 21 and 22 which serve as support and bearing for thewheels 23' and 24, respectively. The body of the crane normally restsupon these wheels 23 and 24 but the upper tracks 17 and 19 prevent theoverturning of the crane during its operation. Spur gears 25 engageracks on the sides of the upper tracks 17 to drive the crane along thetracks. Spur gears 25 are driven by suitable motors such as 26 which maybe operated in either direction to move the crane. The crane base 243includes a suitable circular track which supports the crane cab 27;This. arrangement is conventional. The means for rotating the cab 27about a vertical axis on the base 20 is not illustrated in detail assuch structure is also conventional. The means for rotating the craneabout its vertical axis is not illustrated in detail but the apparatusmay be described generally as including a swinger 29 shown in Figure 3which rotates the cab about the vertical axis on tracks and wheelsenclosed within the, portion 31} of the apparatus as indicated in Figure1.

As indicated in Figure 3, the cab 27 is provided with boom anchormembers 31 and 32 which, as indicated in Figure 1, have axially alignedpivots 33 extending therethrough. These pivots 33 extend through theboom anchors 31 and 32 and through the bifurcated ends 34 of the boom35. These pivots 33 are arranged on a generally horizontal plane andpermit the raising and lowering of the boom 35. The boom itself isrelatively wide at its base including spaced boom sides 36 and 37connected at intervals with cross connections such as 39, it? and 41.The boom gradually tapers in width and is relatively narrow at the crosssection 42 at the boom point. Cross bracing is employed to strengthenthe boom as is conventional in structures of this type.

As indicated diagrammatically in Figure 1, a frame 4-3 extends upwardlyfrom the cab 27 and acts as a support for transverse shafts which guidethe various operating lines. A bracket 44 on the frame 43 supports atransverse shaft 45. upon which is mounted two pairs of sheaves do and47. The boom topping or peaking lines 49 are shown in Figure 6 to extendfrom the boom hoist drum 5%. over one pairof sheaves 46 to a pair ofsheaves 51 mounted on the boom 35 near the point thereof. The lines, 49then return over the second pair of sheaves 47 on the shaft 45 and aredead ended to. the boom at 48. In other words, parallel boom toppinglines extend from sheaves on the shaft 45 to sheaves 51 on a shaft 52near the point of the boom to produce the desired boom lifting action.The topping lines and sheaves are omitted in Figure 5 to simplify theillustration.

The frame as (Figure 1), also supports another bracket 53 which supportsa transverse shaft 54. As shown in Figure 5, the shaft 54 supports threepairs of sheaves which are indicated by the numerals 55, 56 and 57. Apair of sheaves 59 are mounted upon a transverse shaft at the boompoint, the sheaves 59 being in side by side relation. Apair of pulleyblocks 61 are mounted t n-Dir transverse frame 68. at a pointsubstantially spaced from the boom point. These blocks 61 include pulleysheaves 62. The transverse frame 68 also supports the transverse shaft52 which supports the sheaves 51 as well it will be noted that a loadhoisting drum 66 is provided which is shown only diagrammatically inFigure but which simultaneously exerts a pull on two load lines 67 and69. Tracing the load line 67, it will be noted that from the drum 66,the line passes over a sheave 56 on the shaft 54 and extends to a sheave63 on the shaft 52. From the sheave 63 the line extends over a sheave 55and from there over a sheave 59 at the boom point. The line then extendsdownwardly over a sheave 70 forming a part of the load block 71. Theline then diverges upwardly and outwardly to extend over the sheave 62forming a part of the pulley block 61. The line 67 then successivelypasses about the sheave 57, sheave 64 and under sheave 72. The line thenpasses about sheave 74 and becomes a part of the second load line. i

The second load line operates in a similar manner. The line 69 extendsfrom the drum 66 over a sheave 56 to a sheave 63 on the shaft 52. Itthenextends over the second sheave 55 on the frame'of the apparatus andextends to the second sheave 59 at the boom point. The line then extendsparallel to the line 67 to pass over a second sheave 73 forming a partof the load block 71. It then diverges upwardly and outwardly over thesheave 62 and successively passes over the second sheave 57, the secondsheave 64 and beneath the sheave 72. The line then passes about a sheave74 and becomes a part of the first described load line 67. In otherwords, the lines 67 and 69 are in effect integral, so that the pull onthe two lines is equalized.

The shaft 54 is properly located to produce a substantially levelluifing action on the load as the boom is raised or lowered. In otherwords, as the load is raised, the distance between the shafts 54 and 52decreases in amount sufficient to hold the load at a substantiallyconstant level. If the boom is lower, the reverse action takes place andthe portion of the load line supported between the shafts 52 and 54increases sufl'iciently to hold the loadv at an approximately evenlevel. Therefore, the crane possesses level lufling features which havebeen considered highly desirable from an operation standpoint.

It will be seen that the load block 71 is supported by four portions ofthe load line. Two of these portions extend in substantially parallelrelation from the sheaves 59 at the boom point to suitable sheaves 70and 73 on the load block. From the load block the load lines divergeupwardly and outwardly over the widely spaced sheaves 62. As a resultthe load will be suspended by a three point suspension. Because of thisfact rotation of the boom about its vertical axis will not create thesame pendulum effect as if the sheaves 62 were the same distance apartas the sheaves 59. At the same time the load is suspended between pointssubstantially spaced longitudinally of the boom. As a result the effectof centrifugal force is greatly dampened. In other words, the outwardpendulum effect of the load due to centrifugal force is dampened as wellas the lateral pendulum effect.

It will be seen that with this arrangement the boom may be of agenerally conventional type which is wide at its hinged end and tapersto a narrow width at the point. By employing a transversely extendingframe at a point spaced from. the boom point, the proper lateralpositioning of the sheaves to produce the pendulum dampening effect isprovided. Not only will the lateral swinging of the load be dampened butalso the outward swinging of the load is substantially dampened.

In accordance with the patent statutes, I have described the principlesof construction and operation of my cargo crane, and while I haveendeavored to set forth the best embodiment thereof, I desire to have itunderstood that changes may be made within the scope of the followingspears? claims without departing from the spirit of my invention.

I claim:

I. A cargo crane including a crane body, means rotatably supporting saidbody, a boom hingedly secured on a horizontal pivot to said body, thepivotal end of said boom being relatively wide, a pair of closely spacedsheaves supported centrally with respect to the longitudinal axis of theboom adjacent the boom point, a load block, a pair of sheaves supportedby said load block and spaced apart a distancesubstantially equal to thespacing of said sheaves at the boom point, a pair of widely spacedsheaves supported by said boom at a point substantially spaced from thepoint of the boom, and hoist lines extending over said closely spacedsheaves at the boom point, extending in parallel relation to said loadblock, extending about the sheaves of said load block, and over saidwidely spaced sheaves on said boom, said load lines being connected toequalize the load thereupon.

2. The structure described in claim 1 and in which a three part linebetween said boom and said point above said crane body is interposedbetween said widely spaced sheaves and said dead ends of said lines.

3. A substantially level luifing cargo crane including a crane bodyhaving a super structure thereupon, means rotat-ably supporting saidbody, a boom having a relatively wide end, means pivotally connectingsaid relatively wide end to said crane body on a substantiallyhorizontal pivot, a pair of closely spaced sheaves at said boom point, apair of similarly spaced sheaves, a load block connected to saidsimilarly spaced sheaves, a pair of widely spaced sheaves on said boomat points substantially spaced from the boom point, a series of sheaveson said boom at a point spaced from the boom point, and a series ofspaced sheaves on said super structure, a pair of load lines extendingfrom said crane body over sheaves on said super structure and cooperablesheaves on said boom to provide three part lines therebetween, one partof one three part line extending over said sheaves at said boom pointand about said sheaves connected to said pulley block, said load linesextending over said widely spaced sheaves on said boom and overcooperable sheaves on said super structure and on said boom to formthree part lines, the final line of each three part line being connectedat said super structure.

4. The construction described in claim 3 and in which the spacingbetween said sheaves on said super structure and on said boom areproperly located so that elevation or lowering of said boom will holdsaid load block at a substantially horizontal level.

5. The "structure described in claim 4 and in which said boom tapersfrom said relatively wide hinged end to a relatively narrow extremity.

6- The construction described in claim 4 and including a transverseframe secured to said boom to extend laterally thereof, and means onsaid frame supporting said widely spaced sheaves.

References Cited in the file of this patent UNITED STATES PATENTS899,005 Brown Sept. 15, 1908 r 1,111,102 Sawyer Sept. 22, 1914 2,014,544Wilsing Sept. 17, 1935 2,627,984 Senn et al. Feb. 10,1953 2,709,526Hansen May 31, 1955 2,805,781 Senn Sept. 10, 1957 2,807,374 McLean Sept.24, 1957 FOREIGN PATENTS 992,069 France June 27, 1951

